So far, my daughter has had three birthdays even though she was born earlier this year. How is that possible? Simple. My wife, in her infinite wisdom, has decreed that Sasha's birthday is something that ought to be celebrated once a month rather than once a year. Needless to say, this is just an excuse to go shopping.

Why is it that young mothers are so anxious to buy things for their newborns? My theory is that they're making up for lost time. For nine months their purchasing opportunities have been severely limited so when the baby arrives they go on a massive spending spree. It's the post-natal equivalent of eating a lot during pregnancy: shopping for two.

Last weekend Sasha was exactly three months old and Caroline decided that only a really expensive present would do. If you've never visited Westbourne Grove on a Saturday afternoon I don't recommend it. It's like Oxford Street on the last shopping day before Christmas except that everyone has a pushchair. Oof. Ouch. Ow. When Ken Livingstone extends the Congestion Charge to West London I hope he includes the area between Bon Point and Junior Jigsaw.

Looking around, it was clear that men in these situations have two functions: to produce their credit cards and carry the shopping. I saw one man nervously fingering his Barclaycard as his wife inquired about the price of a Burberry nappy bag. Answer: £105. Caroline seemed to think this was quite reasonable on the grounds that I'm such a fashion victim I'd be perfectly happy to lug a nappy bag around provided it had the right designer label.

At least our shopping expedition was interesting from a sociological point of view. In the most advanced cities in the West, fathers now occupy a similar role to that of mothers in the Islamic world. Funnily enough, I spotted a Muslim woman outside Dinny Hall wearing a Burberry burkha. Perhaps I should get one to match my nappy bag.

In the run up to Sasha's birth I'd steeled myself for a shift in my status in the household pecking order. But I wasn't prepared for just how radical this change would be. Three months ago I was king of the castle; now I feel like an awkward member of Queen Caroline's court. To paraphrase Dean Acheson, I've lost an empire and have yet to find a role.

Presumably, something like this went through the mind of Hugh Hefner in 1953, prompting him to start Playboy. When the first issue hit the newsstands Hefner was married and living in cramped accommodation with his wife and baby daughter. The part of Chicago his apartment was in could even be described as the Shepherd's Bush of the midwest.

Unfortunately, there the similarities end. Hefner was 28 in 1953. By the time he reached my age, the Playboy empire had an annual turnover of $48 million and he had his own private jet. The "Big Bunny" was equipped with a disco, a cinema, a wet bar and sleeping quarters for 16. Hef was usually the only male passenger on board.

Still, I'm going to have to make my fortune somehow if I'm to keep my daughter in the style to which she's become accustomed. In the end, Caroline plumped for a baby cashmere outfit from Brora with matching mitts and booties. Kerching! If I have to produce something as extravagant as that every time Sasha passes the three-month mark, what will I get her for her 18th birthday? A GulfStream V?

Perhaps the answer is to start a chain of baby shops that appeal exclusively to men. Instead of designer nappy bags, I'll sell camouflage babygros and miniature paintball guns. They'll be an assault course in the basement--for the dads, naturally--and a furnace into which we can pitch the leopard skin papooses we've been forced to wear. Yummy mummies will be allowed in, but only on the understanding that they'll have to perform lapdances on request.